Center-finding register-calipers



- Patented Aug. 2, |898. G. w. DAVIS.

CENTER FINDING REGISTER` GALIPERS. (Application med v.my 15, 1897.)

(No Model.)

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` rifina- GREER W. DAVIS, OF NEW ALBANY, INDIANA.

SPECIFICATION forming part of Letters Patent No. 608,183, dated August2,1898..

Application filed July 15, 1897. `Serial No. 644,714. (No model.)

To CZZZ whom t may concern:

Be it known that I,` GREER W. DAVIS, a citizen of the United States,residing at New Albany, in the county of Floyd and State of Indiana,have invented certain new and useful Improvements in Center-FindingRegister- Oalipers, of which the following is a specication.

The object of my said invention is to provide an instrument by which thecenters of various bodies may be found; and it consists in an additionor attachment to the instrument known as a register-caliper, or, inother words, the combination, with a registercaliper, of acenter-iinding attachment, all as will be hereinafter more particularlydescribed and claimed.

Referring to the accompanying drawings, which are made a part hereof andon which similar letters of reference indicate similar parts, Figure 1is a top or plan View of an instrument embodying my present inventionFig. 2, a central sectional View thereof as seen from the dotted line 22 in Fig. l; and Fig. 3 a view, on an enlarged scale, as seen from thedotted line 3 3 in Fig. 2.

In said drawings the portions marked A and B represent the two membersof an ordinary register-caliper, said member A being somewhat modifiedin construction, as will be presently described, and C the main 'bar ofmy centering attachment.

As heretofore indicated, the members A and B are of substantially anordinary construction. The end of the member A, however,

upon which the scale is shown is increased in width by so much asappears outside said scale, and in this widened portion is a slit d, asshown most plainly in Fig. 1. The pointer b of the arm B passes over thescale on the widened end of the part A andindicates or;

registers the size of the article being calipered in the ordinarymanner, and the parts A and B are adapted to be locked together in anyposition desired bythe thumb-screw b', which passes through a curvedslot in the part A and engages withV 'the part B, preferably at or nearthe base of the indicator-finger Z), as best shown in Fig. l.

The bar C is preferablya hollow bar and is mounted on an extension ofthe pivot by which theV parts A and B are unite-d. As plainly shown inFigs. 2 and 3, said pivot has a head Z, with an annular groove orneckbelow said head, into which inwardly-extending edges e `onthe barCfproje'ct, as best shown in Fig. 3, and whereby said bar is heldsecurely onto said pivot, there being a slit in the lower side oflsaidhollow bar equal in width to the diameter of said neck. Said slitterminates at thepoint a; in a circular perthrough which said-head maypass in assembling the parts. Atthe rear end of the bar C is amarking-point C', which is preferably in the form'shown, beingadjustable and provided with a lock-screw c. At the forward end a yokeC2 is provided, which is secured to the member A of the caliper by meansof' a thumb-screw A', 4which passes through the slit a and enters asuitable screwthreaded perforation in the under side of said yokefromthe upper side and is adapted to bear upon theupper surfaceofthe bar C.By means of this latter thumb-screw t-he bar C may be locked in anyposition to which it may be adj usted longitudinally. Just behind thisyoke C2 when the same is in its normal position is a perforationextending entirely through the bar C, which forms a sight-hole for theuser. Secured to the yoke C2, immediately above the member A, is a pointc,

`which may be Iobserved throught the sight` `hole just described whenthe bar is properly adjusted, as is shown in Figs. l and 2.

It may be observed before proceeding further with this description thatthe mark on the scale at the point e is the initial or zero ypoint ofthe caliper. Y The scale-marks running npwardly toward the upperend ofthe drawing from this zero marker point are the indicia by which thedistances between the rear ends of the caliper| members are made knownwhen the instrument is used as an out-V side caliper, and those belowsaid zero mark or point are those' which are used when the arms A and Bpass each other, and thus come to position so that the instrument may beused as an inside caliper. The illustration being of the instrument inposition for use as foration equal in diameter tothe head Z and yoke C?.Another thumb-screw c2 enters said vwhich extends rearwardly therefromand IOO an outside caliper, only the scale-marks above the zero-pointare to be considered.

The operation of an instrument provided with or embodying my inventionmay be brieflyv stated as follows: The caliper members are adjusted tofit the article or body to be calipered, so that the points p just, comeagainst its surface. The indicator point or finger b will then indicateupon the scale the diameter of the body being calipered. In theillustration, Fig. l, the instrument is shown with this indicator-fingerpointing to the scalemark 3, thus indicating that the body so beingcalipered is three inches in diameter. Now in order to find the centerof such body without measurement or calculation it is only necessary toswing the bar C so that the point c, carried by the yoke C2, willregister with the scale-mark indicating one and one-half inches, whichof course is half-way betweenv the zero-point and the three-inch mark onthe scale. The point C will then be exactly halfway between the twopoints p. Assume that the center to be found is on a circular body, likethe end of apiece of shafting. By tightening the setscrew A, thussecuring the yoke C2 and the caliper member A tightlytogether, andtightening the set-screw b', thus securing the members A and B of the`caliper firmly together, and loosening the set-screw c2, so that the barC may be moved back and forth through the yoke C2, it is obvious thatthe point C/ can be made to make a mark upon the end of the piece ofshafting of which itis desired to lind the center. Then by turning theinstrument at substantially right angles with its former position andmoving the bar C again another mark will be made, which will intersectthe first mark, and this point of intersection is the center which it isdesired to find.

Having thus fully described my said inven* tion, what I claim as new,and desire to secure by Letters Patent, is-

l. In a center-iinding register-caliper, the combination, of the usualcaliper-arms, pivoted together at a point between their ends, thecaliper contact-points being on one side of said pivot, and one of saidarms having a scale and the other an indeX-iinger on the other side ofsaid pivot, which index-finger is adapted to move over said scale, and abar mounted to swing and also slide on the head of said pivot andextending from between the calipercontact-points on one side of saidpivot to over the scale on the other, and an indeX- iinger connected tosaid bar adjacent to said scale, whereby its position in relationthereto may be determinately adj usted, substantially as set forth.

2. The combination, in a center-finding register-caliper, of the twocaliper-arms pivoted together, `one bearing a scale and the other anindex-finger or pointer, and a bar slidably mounted on the pivot bywhich said caliperarms are united, and provided with a centering-pointat one end and an index-point at the other end, whereby it may be firstadjusted to find a center and then moved longitudinally to mark suchcenter, substantially as set forth.

3. The combination, in acenter-finding register-caliper, of the usualcaliper-arms pivoted together, one bearing a scale or index and theother a linger or pointer, a bar slidably mounted on the pivot whichunites said arms, and a yoke through which one end of said bar passes,said yoke being provided with two fastening or set screws, by one ofwhich it can be secured rigidly to the scale end of the caliper-arm, andby the other of which said bar may be secured to a longitudinally-adjusted position, substantially as set forth.

4. The combination, in a register-caliper, with the caliper-arms, thepivot connecting them formed with a head which projects above said armsand is formed with an annular groove or neck, a scale carried on one ofsaid arms on the opposite side of the pivot from the calipercontact-points, and a hollow bar formed with a slot in its under sideand an aperture to receive said pivot-head, the edges of which slotengage with said groove or neck therein, whereby said bar is held inposition thereon and permitted both a longitudinal and a swingingmovement over said scale,

substantially as set forth.

5. The combination, in a register-caliper, of the caliper-arms A B, thepivot uniting them provided with the head Z, the bar C mounted on saidpivot-head and provided with the center-finding point C', a yoke C2 onthe other end provided with a fastening or set screw A whereby it may besecured to the scale end of the arm A and prevented from rotarymovement, and with a set-screw c2 by which the bar may be clamped andprevented from longitudinal movement, all substantially as set forth.

In witness whereof I have hereuntoset my hand and seal, at New Albany,Indiana, this 10th day of July, A. D. 1897.

v GREER IV. DAVIS. Vitnesses:

GEORGE D. I-IIEB,

DANIEL E. HARTWELL.

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